Re: [PATCH v4] RISC-V: Handle differences between XTheadvector and Vector

[Kito Cheng <kito.cheng@gmail.com>]

> diff --git a/gcc/config/riscv/riscv_th_vector.h b/gcc/config/riscv/riscv_th_vector.h
> new file mode 100644
> index 00000000000..6f47e0c90a4
> --- /dev/null
> +++ b/gcc/config/riscv/riscv_th_vector.h
> @@ -0,0 +1,49 @@
> +/* RISC-V 'XTheadVector' Extension intrinsics include file.
> +   Copyright (C) 2022-2023 Free Software Foundation, Inc.
> +
> +   This file is part of GCC.
> +
> +   GCC is free software; you can redistribute it and/or modify it
> +   under the terms of the GNU General Public License as published
> +   by the Free Software Foundation; either version 3, or (at your
> +   option) any later version.
> +
> +   GCC is distributed in the hope that it will be useful, but WITHOUT
> +   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
> +   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
> +   License for more details.
> +
> +   Under Section 7 of GPL version 3, you are granted additional
> +   permissions described in the GCC Runtime Library Exception, version
> +   3.1, as published by the Free Software Foundation.
> +
> +   You should have received a copy of the GNU General Public License and
> +   a copy of the GCC Runtime Library Exception along with this program;
> +   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#ifndef __RISCV_TH_VECTOR_H
> +#define __RISCV_TH_VECTOR_H
> +
> +#include <stdint.h>
> +#include <stddef.h>
> +
> +#ifndef __riscv_xtheadvector
> +#error "XTheadVector intrinsics require the xtheadvector extension."
> +#else
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +/* NOTE: This implementation of riscv_th_vector.h is intentionally short.  It does
> +   not define the RVV types and intrinsic functions directly in C and C++
> +   code, but instead uses the following pragma to tell GCC to insert the
> +   necessary type and function definitions itself.  The net effect is the
> +   same, and the file is a complete implementation of riscv_th_vector.h.  */
> +#pragma riscv intrinsic "vector"

#pragma riscv intrinsic "theadvector"

Don't reuse `#pragma riscv intrinsic "vector"` to prevent including
riscv_vector.h work with __riscv_xtheadvector.
I know we already guarded with ifndef __riscv_xtheadvector and ifndef
__riscv_vector for now,
but we eventually will remove that due to multi-version function support.

e.g.

a.c compile with -march=rv64gc

a.c:

#include <riscv_vector.h>

void foo(){
...
}

void foo_vector () __attribute__(("arch=+v"));
void foo_vector () {
// Use vector intrinsic to implement something
}